This invention relates to a method for making shaped or figured carbides which are consisted of a self-figurable flock, mass, or bulk of single fibers. More specifically, it relates to a method for making shaped or bulked carbides, in which a flock of cellulosic single fibers which has been prepared by binding the fibers by means of their intertwining properties, is heated for carbonization, whereby it can have a strong tissue afforded with high carbonic characteristics and can present porously shaped fibrous structures.
Heretofore, carbonaceous or carbon substances which are prepared from organic matters (hereinafter called generally as carbides) are employed in various industrial applications in accordance with characteristics they have, viz., adsorption, electrical, adiabatic, thermal resistant, corrosion resistant, mechanical, and other characteristics. In either of such applications, carbides have to be shaped to a form appropriate to a purpose of applications. There are known, for example, powdery, granular, and crashed carbides. And, fibrous carbides which are popularly called as carbon fibers, are available in long or lint fibrous, short or fuzz fibrous, woven, sheet or mat-like, and braided forms. In order to improve their mechanical characteristics, they are often prepared to composite materials by mixing and treating them with other materials such as resins and pitches.
In any case, in order to shape them to a form appropriate to a purpose of applications, they must be subjected to a secondary treatment process in addition to preceding carbonization process. More particularly, in case of obtaining powdery carbides, carbides have to be pulverized and sieved after carbonization, and in case of utilizing long fibrous carbides as flakes, they have to be subjected to a chopping process. And, in case of utilizing long fibrous carbides as woven or braided forms, they have to be subjected, after carbonization, to a weaving or braiding process. In such secondary processes, there are much difficulties to prepare them to a desired form. That is, as carbon fibers have inherently a poor elongation and lack in a bending force, they can tolerate to be woven only into comparatively flat stuff having little bending but not into thick and porous structures.
When short fibrous carbides which have been obtained by chopping as mentioned above, are shaped into sheets or mats by a paper-making process in which an adhesive binder is added as an auxiliary agent to the carbides so that they can be integrally shaped, they can produce only those which are flat and thin. There is observed another disadvantage that such auxiliary agent tends to adversely affect characteristics carbides properly have.
As described above, secondary processing to be adopted for shaping carbides into forms appropriate to their applications, are complex, and in certain cases, it adversely affects characteristics the carbides have and increases a production cost fruitlessly.